Pesticide usage report: Vegetable crops 2013

Summary

This is the seventh survey of pesticide usage on outdoor vegetable crops in Northern Ireland, providing comparative data to that obtained in the previous surveys in 1991, (Jess et al., 1993), 1995 (Kidd et al., 1998), 1999 (Kearns et al., 2002), 2004 (Kearns et al., 2005), 2007 (Withers et al., 2009) and 2011 (Withers et al., 2012). Information on all aspects of pesticide usage was collected from 61 holdings throughout the province. Quantitative data have been adjusted to provide estimates of total pesticide usage.

The majority of vegetable crops grown in Northern Ireland is related to market influences and is normally grown under contract. In 2013, an estimated 1,396 hectares were grown representing an 11% decrease compared with 2011. There was a 35% decrease in the area of leafy and flowerhead brassica crops grown. The area of turnips and swedes grown decreased by 2% when compared with 2011. The area of carrot crops grown decreased by 5% but, parsnip crops increased by 11%. The total area of celery crops increased by 31% when compared to 2011. However, the area of lettuce crops grown decreased by 8%. The areas of onions, spring onions and parsley crops grown decreased by 55%, 59% and 29% respectively.

A total of 117 products comprising 82 active substances were recorded in use in this survey. Fungicides, applied to 23% of the pesticide-treated area, accounted for 20% of the weight of pesticides applied. Herbicides and desiccants accounted for 42% of the pesticide-treated area and 62% of the total weight of pesticides used. Insecticides, applied to 26% of the pesticide-treated area, accounted for 17% of the total weight of pesticides used. Seed treatments applied to vegetable crops accounted for 8% of the pesticide-treated area, representing less than 1% of the weight of active substances applied. Molluscicides accounted 1% of the total pesticide-treated area and less than 1% of the weight of pesticides applied to vegetable crops. Growth regulators accounted for less than 1% of the pesticide-treated area and 1% of the weight of pesticides applied. Biological controls accounted for less than 1% of both the pesticide-treated area and weight of pesticides applied.

By comparison with 2011, the pesticide-treated area increased by 2%, to 13,821 spray hectares (including 27.67 spha of adjuvants), whilst the weight of pesticide active substances applied decreased by 18% to 5,989kg (including 19.09 kg of adjuvants). The average number of spray applications (2.75) remained similar to that recorded in 2011, 2007, 2004 and 1999. The fungicide-treated area decreased by 9%, whilst the weight of fungicide active ingredients decreased by 23%. Overall, the application area of herbicides and desiccants applied increased by 11% however the weight applied decreased by 18%. The insecticide-treated area and the weight of insecticide active substances applied decreased by 3% and 5% respectively. The application of chloronicotinyl insecticides, principally to brassicas, increased. Two groups of insecticides, benzoylurea and tetramic acid, were applied for the first time. Insecticides were most frequently applied to control carrot fly (Psila rosae) on carrot and parsnip crops. However, they were also frequently used to control aphids principally on brassica crops . The area treated with molluscicides decreased by 6% and the weight applied decreased by 61%. An estimated 1,085 hectares of vegetable crops were sown with treated seed, representing a 3% decrease when compared to 2011. However, the weight of seed treatment active substances decreased by 37%. Growth regulators, applied for the first time in 2011exclusively to parsnip crops to delay flowering, a decreased by 20% and 34% in treated area and weight of active substances applied, respectively.

Leafy and flowerhead brassica crops received 15% of the weight of fungicides applied to all vegetable crops, representing 22% of the area of vegetable crops treated with fungicides. The single most commonly used fungicide active substance applied to brassicas was difenoconazole. This was primarily for general fungal control. Carrots and parsnips collectively accounted for 55% of both the weight of fungicide active substances applied and the area treated with fungicides. The formulation boscalid/pyraclostrobin was the most frequently applied fungicide, exclusively used for general fungal control.

Herbicide applications to carrot and parsnip crops represented 55% of the herbicide-treated area and 53% of the weight of herbicides applied. Leafy and flowerhead brassicas accounted for 12% of the herbicide-treated area and 13% of the weight of herbicides applied. Linuron was the herbicide active ingredient most frequently applied to vegetable crops, particularly to carrot and parsnip crops for general weed control. Pendimethalin, metazachlor and glyphosate were also frequently applied.

Carrots and parsnips collectively accounted for 65% of the insecticide-treated area, representing 25% of the weight of insecticide active substances applied. Leafy and flowerhead brassicas accounted for 24% and 56% of the insecticide-treated area and weight applied, respectively. Due to the use of garlic extract, turnips and swedes represented 1.9% of the insecticide-treated area and 11% of the weight of pesticides applied. Pyrethroids were the most frequently used insecticide active substances, particularly lambda-cyhalothrin on carrot and parsnip crops.

Applications of the molluscicide ferric phosphate to leafy brassica and turnip crops for slug control, represented 96% of the molluscicide-treated area and 95% of the weight of molluscicides applied. Methiocarb accounted for the remainder of molluscicide applications.

The pesticide formulation cymoxanil/fludioxonil/metalaxyl-M was the most frequently applied seed treatment, accounting for 44% of the area sown with treated seed and 3.4% of the weight of seed treatments applied. An estimated 37% of all seed treatments were applied to carrot crops, 26% to turnip and swede crops and 21% to parsnip crops.

For further information on this work please contact: Pesticide usage monitoring group